In the present work we determined effects of a sub-chronic exposure to cadmium on some parameters... more In the present work we determined effects of a sub-chronic exposure to cadmium on some parameters of calcium and iodine metabolisms in Meriones shawi, a desert rodent species occupying the arid steppes of Tunisia and other countries. Fourteen jirds of both sex were equally divided into a control group receiving diet without cadmium and a treated group receiving cadmium in the diet during 30, 45, 60 and 90 days. At the end of each period, 5 jirds from each group were sacrificed. In cadmium-treated group, cadmium accumulation and total metallothioneins synthesis in the liver and kidneys were high and dependant on the duration of treatment. Cadmium caused significant modifications in the body weight and in the relative weights of the liver, femur and thyroids, in parallel to a decrease in calcium content in serum and in femur. Cadmium also decreased iodine content in serum and in the thyroids. Several impairments were dependant on the duration of exposure and were more pronounced at the end of the experiment. In conclusion, a sub-chronic exposure to cadmium induces perturbations in calcium and iodine metabolisms in Meriones shawi. However, effects on calcium seem to be more evident. We can conclude also that Meriones shawi is an indicator of cadmium presence in arid environments.
Ecotoxicology and Environmental Safety, Jan 1, 2011
Zinc (Zn) reduces cadmium (Cd)-induced toxicity in the liver although it increases Cd tissue burd... more Zinc (Zn) reduces cadmium (Cd)-induced toxicity in the liver although it increases Cd tissue burden in some conditions; hence, the present study is designed to study the relationships between Cd, Zn and antioxidants in the liver of rats exposed to Cd. Livers of male rats which received orally relatively high doses of Cd (200 mg Cd/L as Cd chloride or Cd (200 mg/L)+Zn (500 mg Zn as Zn chloride) during five weeks, were investigated. Cd induced an accumulation of Cd and Zn in parallel to depletion in important variables (GSH, GSH/GSSG, CuZn-SOD and GPx activities) and to elevation in others (Cd/Zn and GSSG). Cd, did not affect CuZn SOD/GPx, nor Mn-SOD in the liver. Cd accumulation, Cd/Zn, CuZn SOD activity and CuZn SOD/GPx, was increased remarkably under Zn action. Zn supply ameliorated GSH level and partially reversed the decrease in GSH/GSSG, but it did not ameliorate GPx activity. Analysis showed high correlations between Cd and the majority of the variables, while Zn was positively correlated with only GSSG. We suggest from our results that Zn has indirect ameliorative effects on Cd-induced toxicity in the liver and that the increase in Cd retention is probably the key mechanism modulating, in the case of relatively high doses of Cd, the antioxidant response during exposure to Cd and Zn.► Zinc supply diminished cadmium-induced oxidative stress in the liver of the rat while it increased cadmium retention in the organ. ► Cadmium was highly connected with many antioxidants (SOD, GPx, GSH, Se, Zn), while Zn was not. ► Zn ameliorative effects are thus thought to be mediated by indirect mechanisms, based on the level of cadmium retention.
Zinc (Zn) reverses cadmium (Cd)-induced toxicity in kidneys although it increases Cd tissue burde... more Zinc (Zn) reverses cadmium (Cd)-induced toxicity in kidneys although it increases Cd tissue burden, hence, the present study is designed to study the relationships between Cd, Zn and antioxidants in the kidneys of rats exposed to Cd orally. Male rats received either tap water, Cd or Cd + Zn in their drinking water during five weeks. Cd-induced increase in Cd and Zn accumulation was accompanied by a decrease in important variables (GSH, GSH/GSSG, CuZn SOD and GPx activities) and by an increase in others (Cd/Zn, GSSG and CuZn SOD/GPx). Zn supply intensified Cd retention and Cd/Zn; it amplified CuZn SOD activity, CuZn SOD/GPx and GSH/GSSG compared to normal values, but had no effect on Zn content increase. Besides, it ameliorated GPx activity and corrected GSSG level. High positive correlations were found between Cd concentrations and the majority of the studied variables suggesting a direct influence of Cd on them. Zn concentration had positive correlation with CuZn SOD/GPx, and negative one with GPx activity, which reflects an indirect protective effect of Zn. In conclusion, our results suggest that Zn increases Cd tissue retention in the kidney and that is probably the key mechanism of the protective effect of Zn.
Archives of Environmental Contamination and Toxicology, Jan 1, 2010
Cadmium (Cd), one of the most widely distributed heavy metals, is highly toxic to humans and anim... more Cadmium (Cd), one of the most widely distributed heavy metals, is highly toxic to humans and animals. It is well known that zinc (Zn) and selenium (Se) administration reduce the Cd-induced toxicity and that metallothioneins can have a protective effect to mitigate Cd toxicity in biological systems. In this study we report the expression analysis of the two metallothioneines gene classes MT-1 and MT-2 as well as the total metalloprotein content in the liver of rats exposed to Cd (200 ppm), Cd + Zn (200 ppm + 500 ppm), Cd + Se (200 ppm + 0.1 ppm) or Cd + Zn + Se (200 ppm + 500 ppm + 0.1 ppm) in their drinking water for 35 days. Metals accumulation was quantified in rat liver. Cd decreased significantly the hepatic concentrations of Se and increased those of Zn. The treatment of Cd-exposed rats with Se alone or combined with Zn reversed the Cd-induced depletion of Se concentrations in the liver. However, Zn or Zn + Se administration significantly increased the liver Cd uptake and had no effect on the Cd-induced increase in hepatic concentrations of Zn. The molecular assay showed a decreasing trend of MT-1 relative gene expression levels in animals supplemented with Zn (6.87-fold), Se (3.58-fold), and their combination (1.69-fold) when compared to Cd-treated animals (16.22-fold). Upregulation of the MT-2 expression were recorded in all conditions, although fold induction levels were less pronounced than MT-1 expressions. Our data suggest that the well-established protective effect of Zn and Se against Cd-induced toxicity passes through non-MT gene expression mechanisms, being more dependent on the oxidative stress status of the cell.
Experimental and Toxicologic Pathology, Jan 1, 2010
The aim of this study was to evaluate the potential benefit of combined treatment with zinc (Zn) ... more The aim of this study was to evaluate the potential benefit of combined treatment with zinc (Zn) and selenium (Se) in reversing cadmium (Cd)-induced oxidative stress in erythrocytes, compared to Se or Zn treatment alone in rats exposed to Cd. For this purpose, 30 adult male Wistar albino rats were equally divided into control and four treated groups received either 200 ppm Cd (as CdCl2), 200 ppm Cd+500 ppm Zn (as ZnCl2), 200 ppm Cd+0.1 ppm Se (as Na2SeO3), or 200 ppm Cd+500 ppm Zn+0.1 ppm Se in their drinking water for 35 days. Marked alterations of antioxidative system were found in Cd-treated rats. Activities of catalase (CAT) and glutathione peroxidise (GSH-Px) as well as the total glutathione (GSH) contents in erythrocytes were significantly decreased, whereas the activity of total superoxide dismutase (SOD) was significantly increased. The treatment of Cd-exposed rats with Se alone had no significant effect on the Cd-induced increase in the SOD activity but increased significantly the CAT and GSH-Px activities and partially reversed Cd-induced depletion of GSH levels in erythrocytes. The treatment of Cd-exposed animals with Zn alone partially reversed Cd-induced increase in SOD activity and Cd-induced decrease in GSH-Px activity. The combined treatment of Cd-exposed animals with Se and Zn was more effective than that with either of them alone in reversing Cd-induced decrease in CAT and GSH-Px activities and Cd-induced increase in SOD activity. This treatment also partially restored Cd-induced depletion of GSH. These results could be important for the further development of better treatments for people and/or animals exposed to Cd.
Ecotoxicology and Environmental Safety, Jan 1, 2009
Cadmium (Cd) is a very harmful environmental pollutant that transfers between various levels of t... more Cadmium (Cd) is a very harmful environmental pollutant that transfers between various levels of the food chain. To study the protective effect of Se and Zn on Cd-induced oxidative stress in livers, male rats received either, tap water, Cd, Cd+Zn, Cd+Se or Cd+Zn+Se in their drinking water, for 35 days. The activities of total superoxide dismutase (SOD), copper, zinc-superoxide dismutase (CuZn SOD), glutathione peroxidase (GPx) and catalase (CAT), malondialdehyde (MDA) level and the ratio of CuZn SOD to GPx activity, were determined in the liver. Exposure to Cd lowered total SOD, CuZn SOD, GPx and CAT activities, while it increased MDA level and the ratio of CuZn SOD to GPx activity, in the organ studied. With Se or Zn administration during exposure to Cd, only partial corrective effects on Cd-induced oxidative stress in the liver have been observed, while Se and Zn together assured a more efficient protection of the organ against the observed oxidative stress.
The present study was conducted to investigate whether the combined treatment with Se and Zn offe... more The present study was conducted to investigate whether the combined treatment with Se and Zn offers more beneficial effects than that provided by either of them alone in reversing Cd-induced oxidative stress in the kidney of rat. For this purpose, 30 adult male Wistar albino rats, equally divided into control and four treated groups, received either 200 ppm Cd (as CdCl2), 200 ppm Cd + 500 ppm Zn (as ZnCl2), 200 ppm Cd + 0.1 ppm Se (as Na2SeO3), or 200 ppm Cd + 500 ppm Zn + 0.1 ppm Se in their drinking water for 35 days. The results showed that Cd treatment decreased significantly the catalase (CAT) and glutathione peroxidase (GSH-Px) activities, whereas the superoxide dismutase (SOD) activity and the renal levels of lipid peroxidation (as malondialdehyde, MDA) were increased compared to control rats. The treatment of Cd-exposed rats with Se alone had no significant effect on the Cd-induced increase in the MDA concentrations but increased significantly the CAT activities and reversed Cd-induced increase in SOD activity. It also partially prevented Cd-induced decrease in GSH-Px activity. The treatment of Cd-exposed animals with Zn alone increased significantly the CAT activity and partially protected against Cd-induced increase in the MDA concentrations, whereas it had no significant effect on the Cd-induced increase in SOD activity and decrease in GSH-Px activity. The combined treatment of Cd-exposed animals with Se and Zn was more effective than that with either of them alone in reversing Cd-induced decrease in CAT and GSH-Px activities and Cd-induced increase in MDA concentrations. Results demonstrated beneficial effects of combined Se and Zn treatment in Cd-induced oxidative stress in kidney and suggest that Se and Zn can have a synergistic role against Cd toxicity.
To assess the co-effect of Se and Zn on Cd accumulation in the liver and kidney and on their hist... more To assess the co-effect of Se and Zn on Cd accumulation in the liver and kidney and on their histology, male rats were exposed either to Cd, Cd + Zn, Cd + Se, or Cd + Zn + Se in their drinking water, during 35 days. Exposure to Cd resulted in its accumulation in the liver and kidney. In the Cd–Zn and Cd–Zn–Se groups, Cd contents in the two organs were significantly (p < 0.01) higher than those in the Cd group. Se did not induce any significant difference in hepatic and renal concentrations of Cd in comparison to Cd-treated group. Light microscopic examination indicated severe histological changes in the two organs under Cd influence. Se or Zn partially alleviated the damage observed in the liver. The same effect was remarked in the kidney with Se, but no differences in the renal histological structure have been observed between the Zn–Cd and the control groups. With Se and Zn simultaneous treatment during Cd exposure, the observed morphological changes had practically disappeared from the liver, but were only reduced in the kidney. Conclusion: Se and Zn can have a cooperative effect in the protection against Cd-induced structural damage in the liver but not in the kidney.
In the present work we determined effects of a sub-chronic exposure to cadmium on some parameters... more In the present work we determined effects of a sub-chronic exposure to cadmium on some parameters of calcium and iodine metabolisms in Meriones shawi, a desert rodent species occupying the arid steppes of Tunisia and other countries. Fourteen jirds of both sex were equally divided into a control group receiving diet without cadmium and a treated group receiving cadmium in the diet during 30, 45, 60 and 90 days. At the end of each period, 5 jirds from each group were sacrificed. In cadmium-treated group, cadmium accumulation and total metallothioneins synthesis in the liver and kidneys were high and dependant on the duration of treatment. Cadmium caused significant modifications in the body weight and in the relative weights of the liver, femur and thyroids, in parallel to a decrease in calcium content in serum and in femur. Cadmium also decreased iodine content in serum and in the thyroids. Several impairments were dependant on the duration of exposure and were more pronounced at the end of the experiment. In conclusion, a sub-chronic exposure to cadmium induces perturbations in calcium and iodine metabolisms in Meriones shawi. However, effects on calcium seem to be more evident. We can conclude also that Meriones shawi is an indicator of cadmium presence in arid environments.
Ecotoxicology and Environmental Safety, Jan 1, 2011
Zinc (Zn) reduces cadmium (Cd)-induced toxicity in the liver although it increases Cd tissue burd... more Zinc (Zn) reduces cadmium (Cd)-induced toxicity in the liver although it increases Cd tissue burden in some conditions; hence, the present study is designed to study the relationships between Cd, Zn and antioxidants in the liver of rats exposed to Cd. Livers of male rats which received orally relatively high doses of Cd (200 mg Cd/L as Cd chloride or Cd (200 mg/L)+Zn (500 mg Zn as Zn chloride) during five weeks, were investigated. Cd induced an accumulation of Cd and Zn in parallel to depletion in important variables (GSH, GSH/GSSG, CuZn-SOD and GPx activities) and to elevation in others (Cd/Zn and GSSG). Cd, did not affect CuZn SOD/GPx, nor Mn-SOD in the liver. Cd accumulation, Cd/Zn, CuZn SOD activity and CuZn SOD/GPx, was increased remarkably under Zn action. Zn supply ameliorated GSH level and partially reversed the decrease in GSH/GSSG, but it did not ameliorate GPx activity. Analysis showed high correlations between Cd and the majority of the variables, while Zn was positively correlated with only GSSG. We suggest from our results that Zn has indirect ameliorative effects on Cd-induced toxicity in the liver and that the increase in Cd retention is probably the key mechanism modulating, in the case of relatively high doses of Cd, the antioxidant response during exposure to Cd and Zn.► Zinc supply diminished cadmium-induced oxidative stress in the liver of the rat while it increased cadmium retention in the organ. ► Cadmium was highly connected with many antioxidants (SOD, GPx, GSH, Se, Zn), while Zn was not. ► Zn ameliorative effects are thus thought to be mediated by indirect mechanisms, based on the level of cadmium retention.
Zinc (Zn) reverses cadmium (Cd)-induced toxicity in kidneys although it increases Cd tissue burde... more Zinc (Zn) reverses cadmium (Cd)-induced toxicity in kidneys although it increases Cd tissue burden, hence, the present study is designed to study the relationships between Cd, Zn and antioxidants in the kidneys of rats exposed to Cd orally. Male rats received either tap water, Cd or Cd + Zn in their drinking water during five weeks. Cd-induced increase in Cd and Zn accumulation was accompanied by a decrease in important variables (GSH, GSH/GSSG, CuZn SOD and GPx activities) and by an increase in others (Cd/Zn, GSSG and CuZn SOD/GPx). Zn supply intensified Cd retention and Cd/Zn; it amplified CuZn SOD activity, CuZn SOD/GPx and GSH/GSSG compared to normal values, but had no effect on Zn content increase. Besides, it ameliorated GPx activity and corrected GSSG level. High positive correlations were found between Cd concentrations and the majority of the studied variables suggesting a direct influence of Cd on them. Zn concentration had positive correlation with CuZn SOD/GPx, and negative one with GPx activity, which reflects an indirect protective effect of Zn. In conclusion, our results suggest that Zn increases Cd tissue retention in the kidney and that is probably the key mechanism of the protective effect of Zn.
Archives of Environmental Contamination and Toxicology, Jan 1, 2010
Cadmium (Cd), one of the most widely distributed heavy metals, is highly toxic to humans and anim... more Cadmium (Cd), one of the most widely distributed heavy metals, is highly toxic to humans and animals. It is well known that zinc (Zn) and selenium (Se) administration reduce the Cd-induced toxicity and that metallothioneins can have a protective effect to mitigate Cd toxicity in biological systems. In this study we report the expression analysis of the two metallothioneines gene classes MT-1 and MT-2 as well as the total metalloprotein content in the liver of rats exposed to Cd (200 ppm), Cd + Zn (200 ppm + 500 ppm), Cd + Se (200 ppm + 0.1 ppm) or Cd + Zn + Se (200 ppm + 500 ppm + 0.1 ppm) in their drinking water for 35 days. Metals accumulation was quantified in rat liver. Cd decreased significantly the hepatic concentrations of Se and increased those of Zn. The treatment of Cd-exposed rats with Se alone or combined with Zn reversed the Cd-induced depletion of Se concentrations in the liver. However, Zn or Zn + Se administration significantly increased the liver Cd uptake and had no effect on the Cd-induced increase in hepatic concentrations of Zn. The molecular assay showed a decreasing trend of MT-1 relative gene expression levels in animals supplemented with Zn (6.87-fold), Se (3.58-fold), and their combination (1.69-fold) when compared to Cd-treated animals (16.22-fold). Upregulation of the MT-2 expression were recorded in all conditions, although fold induction levels were less pronounced than MT-1 expressions. Our data suggest that the well-established protective effect of Zn and Se against Cd-induced toxicity passes through non-MT gene expression mechanisms, being more dependent on the oxidative stress status of the cell.
Experimental and Toxicologic Pathology, Jan 1, 2010
The aim of this study was to evaluate the potential benefit of combined treatment with zinc (Zn) ... more The aim of this study was to evaluate the potential benefit of combined treatment with zinc (Zn) and selenium (Se) in reversing cadmium (Cd)-induced oxidative stress in erythrocytes, compared to Se or Zn treatment alone in rats exposed to Cd. For this purpose, 30 adult male Wistar albino rats were equally divided into control and four treated groups received either 200 ppm Cd (as CdCl2), 200 ppm Cd+500 ppm Zn (as ZnCl2), 200 ppm Cd+0.1 ppm Se (as Na2SeO3), or 200 ppm Cd+500 ppm Zn+0.1 ppm Se in their drinking water for 35 days. Marked alterations of antioxidative system were found in Cd-treated rats. Activities of catalase (CAT) and glutathione peroxidise (GSH-Px) as well as the total glutathione (GSH) contents in erythrocytes were significantly decreased, whereas the activity of total superoxide dismutase (SOD) was significantly increased. The treatment of Cd-exposed rats with Se alone had no significant effect on the Cd-induced increase in the SOD activity but increased significantly the CAT and GSH-Px activities and partially reversed Cd-induced depletion of GSH levels in erythrocytes. The treatment of Cd-exposed animals with Zn alone partially reversed Cd-induced increase in SOD activity and Cd-induced decrease in GSH-Px activity. The combined treatment of Cd-exposed animals with Se and Zn was more effective than that with either of them alone in reversing Cd-induced decrease in CAT and GSH-Px activities and Cd-induced increase in SOD activity. This treatment also partially restored Cd-induced depletion of GSH. These results could be important for the further development of better treatments for people and/or animals exposed to Cd.
Ecotoxicology and Environmental Safety, Jan 1, 2009
Cadmium (Cd) is a very harmful environmental pollutant that transfers between various levels of t... more Cadmium (Cd) is a very harmful environmental pollutant that transfers between various levels of the food chain. To study the protective effect of Se and Zn on Cd-induced oxidative stress in livers, male rats received either, tap water, Cd, Cd+Zn, Cd+Se or Cd+Zn+Se in their drinking water, for 35 days. The activities of total superoxide dismutase (SOD), copper, zinc-superoxide dismutase (CuZn SOD), glutathione peroxidase (GPx) and catalase (CAT), malondialdehyde (MDA) level and the ratio of CuZn SOD to GPx activity, were determined in the liver. Exposure to Cd lowered total SOD, CuZn SOD, GPx and CAT activities, while it increased MDA level and the ratio of CuZn SOD to GPx activity, in the organ studied. With Se or Zn administration during exposure to Cd, only partial corrective effects on Cd-induced oxidative stress in the liver have been observed, while Se and Zn together assured a more efficient protection of the organ against the observed oxidative stress.
The present study was conducted to investigate whether the combined treatment with Se and Zn offe... more The present study was conducted to investigate whether the combined treatment with Se and Zn offers more beneficial effects than that provided by either of them alone in reversing Cd-induced oxidative stress in the kidney of rat. For this purpose, 30 adult male Wistar albino rats, equally divided into control and four treated groups, received either 200 ppm Cd (as CdCl2), 200 ppm Cd + 500 ppm Zn (as ZnCl2), 200 ppm Cd + 0.1 ppm Se (as Na2SeO3), or 200 ppm Cd + 500 ppm Zn + 0.1 ppm Se in their drinking water for 35 days. The results showed that Cd treatment decreased significantly the catalase (CAT) and glutathione peroxidase (GSH-Px) activities, whereas the superoxide dismutase (SOD) activity and the renal levels of lipid peroxidation (as malondialdehyde, MDA) were increased compared to control rats. The treatment of Cd-exposed rats with Se alone had no significant effect on the Cd-induced increase in the MDA concentrations but increased significantly the CAT activities and reversed Cd-induced increase in SOD activity. It also partially prevented Cd-induced decrease in GSH-Px activity. The treatment of Cd-exposed animals with Zn alone increased significantly the CAT activity and partially protected against Cd-induced increase in the MDA concentrations, whereas it had no significant effect on the Cd-induced increase in SOD activity and decrease in GSH-Px activity. The combined treatment of Cd-exposed animals with Se and Zn was more effective than that with either of them alone in reversing Cd-induced decrease in CAT and GSH-Px activities and Cd-induced increase in MDA concentrations. Results demonstrated beneficial effects of combined Se and Zn treatment in Cd-induced oxidative stress in kidney and suggest that Se and Zn can have a synergistic role against Cd toxicity.
To assess the co-effect of Se and Zn on Cd accumulation in the liver and kidney and on their hist... more To assess the co-effect of Se and Zn on Cd accumulation in the liver and kidney and on their histology, male rats were exposed either to Cd, Cd + Zn, Cd + Se, or Cd + Zn + Se in their drinking water, during 35 days. Exposure to Cd resulted in its accumulation in the liver and kidney. In the Cd–Zn and Cd–Zn–Se groups, Cd contents in the two organs were significantly (p < 0.01) higher than those in the Cd group. Se did not induce any significant difference in hepatic and renal concentrations of Cd in comparison to Cd-treated group. Light microscopic examination indicated severe histological changes in the two organs under Cd influence. Se or Zn partially alleviated the damage observed in the liver. The same effect was remarked in the kidney with Se, but no differences in the renal histological structure have been observed between the Zn–Cd and the control groups. With Se and Zn simultaneous treatment during Cd exposure, the observed morphological changes had practically disappeared from the liver, but were only reduced in the kidney. Conclusion: Se and Zn can have a cooperative effect in the protection against Cd-induced structural damage in the liver but not in the kidney.
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